The invention relates to transport mechanical engineering, more specifically to wheel sets of transport devices
Widely-known wheel sets comprise an axle and wheels, the rims of which are rigidly connected to the axle whereas the running surfaces are formed on rims rigidly connected to hubs.
When the known wheel set is used, the wheels cannot move at different angular speeds, and this results in increased wear on the running surfaces of the wheels and the rails and also increases the consumption of energy.
There is also a known set with a friction slip limiter, wherein one wheel is rigidly connected to the axle whereas the other is connected to the axle via bushes and a front friction clutch adjusted to a limiting torque. (SU, No. 1782776, Int. Cl. B60B 39/14). In this wheel set, owing to the constant compressive force of the front friction clutch, there is low efficiency in equalizing the angular speeds of the wheels, and the wheel set operates only on a rail track with a very small radius of curvature, which limits its range of usefulness.
In addition, the wheel set has a complicated construction and is complicated in use.
The wheel set nearest in technical nature to the applied-for invention comprises an axle and wheels having their hubs rigidly connected to the axle whereas the running surfaces are formed on rims, one of which is rigidly connected to the hub whereas the other is connected thereto with possibility of rotation (DE, No. 3740140, Int. Cl. B60B 19/00).
The distinguishing feature of this wheel set is that the rim is connected to the hub via worm gears and control drives, fitted in the wheel. This greatly increases the complexity of the construction of the set, owing to the need for a system of control of drives, connected to transducers disposed along the track of the transport device.
The invention is based on the problem of constructing a wheel set for a transport device wherein the connecting unit between the hub and the rim is changed so as automatically to reduce the resistance to motion of the transport device and simultaneously simplify the construction of the wheels and increase the reliability of the wheel set, and also reduce the wear on the running surfaces of the wheels and the rail.
To this end, in the wheel set of a transport device according to the invention, the inner surface of the rim and the surface in contact therewith are in the form of surfaces of rotation, and the parameters of the rim and the hub are chosen such that the torque defined by the frictional forces in the zone of contact between the surfaces is very near the torque applied to a wheel of the set when it moves from its position and travels.
The shape of the surfaces in contact, i.e. two surfaces of rotation, increases the coefficient of friction compared with the coefficient of friction between the wheel and the rail.
In addition, contact along the surfaces of rotation enables the inevitable slip to be transferred from the area of contact between the wheel and rail to the internal zone of the wheel, which can be made of wear-resistant material and with set friction parameters.